Nowadays, with increasing development of high technology industries, electronic devices are widely used in our daily lives. For most electronic devices, a variety of electronic lighting elements are used to generate light signals to notify the user. For example, a red light signal is shown if an electric hot-water heater is cooking water. After the water contained in the electric hot-water heater has been boiled, the red light signal is switched to a green light signal to notify the user that the water has been boiled and is now feasible to drink. The examples of using electronic lighting elements in electronic devices to notify the users are too numerous to be enumerated. For example, electronic lighting elements may be utilized in computer systems and the peripheral devices thereof. As known, an input device such as a mouse is an important peripheral device of a computer for establishing contact between the computer and the user. The mouse has an indicating lamp to emit light signals to notify the user of different operating statuses of the mouse.
Hereinafter, an input device having an indicating lamp and the operations of the input device will be illustrated in more details with reference to FIG. 1. FIG. 1 is a schematic exploded view of an input device having an indicating lamp according to the prior art. The input device 1 principally comprises a case 14 and an electronic lighting module. A case perforation 141 is formed in the case 14. The electronic lighting module comprises a printed circuit board 10, an electronic lighting element 11, a light guide post 13 and a lamp cover 16. The electronic lighting element 11 is disposed on the printed circuit board 10 for emitting light beams. The light guide post 13 is arranged between the case 14 and the electronic lighting element 11 for guiding the light beams. For assembling the input device 1, an end of the light guide post 13 is contacted with the electronic lighting element 11 and the other end of the light guide post 13 is inserted into the case perforation 141. The length H1 of the light guide post 13 is substantially identical to the vertical distance between the electronic lighting element 11 and the case perforation 141. In addition, the electronic lighting element 11 is aligned with the case perforation 141. That is, the electronic lighting element 11 and the case perforation 141 are arranged along the same vertical line. The lamp cover 16 is disposed on the surface of the case 14 and shelters the case perforation 141 from being exposed. During operation of the input device 1, the electronic lighting element 11 emits light beams. Since the electronic lighting element 11 is contacted with the light guide post 13, the light beams are guided by the light guide post 13 to the case perforation 141. Since the lamp cover 16 is made of transparent material, the light beams finally penetrate through the lamp cover 16 so as to indicate a light signal on the surface of the input device 1.
The conventional input device having an indicating lamp, however, still has some drawbacks. For example, the light beams are not uniformly distributed on the lamp cover. Due to a light gathering property of the electronic lighting element, the majority of the light beams emitted by the electronic lighting element are focused on a spot. The light beams are then conducted through the light guide post to the lamp cover such that the light beams are not uniformly distributed on the lamp cover. Under this circumstance, the light signal is not pleasing to the eye and readily discomforts the vision of the user.
Therefore, there is a need of providing an input device having an indicating lamp for uniformly displaying the light signal so as to obviate the drawbacks encountered from the prior art.